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Decimal reduction time of bacterial spores is 23 min at 121°C and the death kinetics follow first order. One liter medium containing 105 spores per mL was sterilized for 10 min at 121°C in a batch sterilizer. The number of spores in
the medium after sterilization (assuming destruction of spores in heating and cooling period is negligible) will be ___________×107.
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- 3.6 to 3.8
- 2.1 to 2.8
- 6.3 to 8.3
- None of the above
Correct Option: A
| Dr = | ||
| Ka |
| ∴ Kd = | , Dr = 23 min | |
| Dr |
⇒ Kd = 0.100 min–1
Now , N0 = 105 × 1000 = 108 spores in 1 litre
| ∴ ln | = Kdt , t = 10 min | |
| N1 |
| ∴ ln | = 0.1 × 10 ⇒ | = e1 = 2.718 | ||
| N1 | N1 |
∴ N1 = 3.678 × 107 spores
